(R)-2-Fmoc-amino-4-cyanobutyric acid

4-(Dihydroxyboryl)-3-nitrobenzoic acid, C7H6BNO6, M(r) = 210.94, monoclinic, P2(1)/n, a = 10.542 (2), b = 6.411 (1), c = 13.105 (4) A, beta = 106.47 (2) degrees, V = 849.3 (4) A3, Z = 4, Dm = 1.65 (flotation in CCl4/1,2-dibromoethane), Dx = 1.649 Mg m-3, lambda(Mo K alpha) = 0.71073 A, mu = 0.135 mm-1, F(000) = 432, T = 293 K, R = 0.0530 for 1328 observed reflections with F > 2 sigma(F). The molecule is flat [the carboxy and nitro groups are rotated 5.8 (4) and 1.9 (4) degrees, respectively, out of the plane] with the boronic acid group almost normal to the plane of the benzene ring, 92.4 (3) degrees. The B atom and one O atom of the nitro group are separated by only 2.457 (4) A implying an interaction that is consistent with observed chemical behavior.

The composition of diet strongly affects acid-base homeostasis. Western diets abundant in acidogenic foods (meat and cheese) and deficient in alkalizing foods (fruits and vegetables) increase dietary acid load (DAL). A high DAL has been associated with numerous health repercussions, including cardiovascular disease and type-2-diabetes. Plant-based diets have been associated with a lower DAL; however, the number of trials exploring this association is limited. This randomized-controlled trial sought to examine whether an isocaloric vegan diet lowers DAL as compared to a meat-rich diet. Forty-five omnivorous individuals were randomly assigned to a vegan diet (n = 23) or a meat-rich diet (n = 22) for 4 weeks. DAL was determined using potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores at baseline and after 3 and 4 weeks, respectively. After 3 weeks, median PRAL (-23.57 (23.87)) and mean NEAPR (12.85 ± 19.71) scores were significantly lower in the vegan group than in the meat-rich group (PRAL: 18.78 (21.04) and NEAPR: 60.93 ± 15.51, respectively). Effects were mediated by a lower phosphorus and protein intake in the vegan group. Our study suggests that a vegan diet is a potential means to reduce DAL, whereas a meat-rich diet substantially increases the DAL burden.

Herein we report a bis-boric acid-mediated regioselective reductive aminolysis of 3,4-epoxy alcohols, providing new access to prepare amino diols in high diastereofidelity directly starting from nitroarenes. Notably, this step-economical process is enabled by the essential dual function of bis-boric acid, which is engaged initially in the 4,4'-bipyridine-catalyzed reduction of nitro compounds as the reductant and subsequently promotes the ring opening reaction of 3,4-epoxy alcohols with the in situ-generated anilines.